Revert "Implement percentage-closer soft shadows (PCSS). (bevyengine#13497)"

This reverts commit 2ae5a21.

Author: coreh

Cargo.toml

@@ -3467,17 +3467,6 @@ description = "Demonstrates animation masks"
 category = "Animation"
 wasm = true
 
-[[example]]
-name = "pcss"
-path = "examples/3d/pcss.rs"
-doc-scrape-examples = true
-
-[package.metadata.example.pcss]
-name = "Percentage-closer soft shadows"
-description = "Demonstrates percentage-closer soft shadows (PCSS)"
-category = "3D Rendering"
-wasm = false
-
 [profile.wasm-release]
 inherits = "release"
 opt-level = "z"